Study on the tribological behavior of the ceramic coating formed on magnesium alloy by pulse-current microarc oxidation

摘要

Microarc oxidation is a recently developed surface treatment technology under anodic oxidation. Through microarc oxidation, ceramic coating is directly formed on the surface of magnesium alloy, by which its surface property is greatly improved. In this paper, a dense ceramic oxide coating was prepared on a AZ31 magnesium alloy by microarc oxidation in a Na_2SiO_3 electrolytic solution. Surface morphology and phase composition were analysed using scanning electron microscopy (SEM), X-ray diffraction (XRD). The tribological behavior of the micro-arc oxidation ceramic coating under dry sliding against SAE52100 steel was evaluated on a ball-on-disc test rig. The results showed that the AZ31 alloy was characterized by adhesion wear and scuffing under dry sliding against the steel, while the surface micro-arc oxidation ceramic coating experienced much abated adhesion wear and scuffing under the same testing condition. The micro-arc oxidation ceramic coating showed good friction-reducing and fair antiwear ability in dry sliding against the steel.